This invention relates to a solid state image sensing device for image sensing.
2. Description of the Prior Art
In a frame transfer type area (two-dimensional) sensor, the number of cells in the longitudinal direction of the image sensing portion has been 245, namely, about one-half of the number of scanning lines, in the case of NTSC system, and the number of picture elements which can be stored in each cell at a time has been 245 which corresponds to one field because each cell has been provided with the functions of photosensing and transfer, and images corresponding to one field have been obtained by effecting an interlace operation which comprises reading out a signal charge corresponding to the one field, thereafter effecting image sensing by moving the effective photosensitive area of each cell, and subsequently reading out the amount corresponding to the one field.
Such a system matches the NTSC television system very well and is characterized by its ability to provide an image of excellent resolution in spite of the small number of cells.
On the other hand, in recent years, studies and developments have been carried out for sensing images by using an image sensing device such as CCD instead of the conventional silver salt film known as the video still camera or the video photography and magnetically recording the sensed images. Where the conventional frame transfer type area sensor is used in such a system, there is the disadvantage that if an attempt is made to record one frame to obtain a high quality of image, the resultant image comprises two fields deviated a little from each other in time, or deviated from each other by 1/60 sec. in terms of TV signal rate and when the image of a moving object is sensed, there is only obtained an unsightly image and if one-field recording is adopted to avoid such a phenomenon, the resolution in vertical direction is reduced to about one-half.